Technical note: Excel spreadsheet calculation of the Henssge equation as an aid to estimating postmortem interval

Area of Science:

• Forensic Science
• Biophysics
• Computational Biology

Background:

• Estimating the postmortem interval is critical in forensic investigations when the time of death is unknown.
• The Henssge equation, based on postmortem cooling and body parameters, is a key method for this estimation.
• Traditional methods for solving the Henssge equation, such as nomograms, can be cumbersome and less accessible with modern technology.

Purpose of the Study:

• To develop user-friendly computational tools for solving the Henssge equation.
• To provide accurate and accessible methods for estimating the postmortem interval using readily available software.
• To facilitate the application of the Henssge equation in forensic casework through digital solutions.

Main Methods:

• Development of two distinct Excel spreadsheets for numerical analysis of the Henssge equation.
• One spreadsheet utilizes an iterative approach with the Solver add-in for high accuracy.
• The second spreadsheet employs forward calculation with XLOOKUP to find the closest approximation of the postmortem interval.

Main Results:

• Both developed Excel spreadsheets provide effective numerical solutions to the Henssge equation.
• The iterative method offers a highly accurate estimation of the postmortem interval.
• The forward calculation method provides a practical and approximate solution, suitable for rapid analysis.

Conclusions:

• The created Excel spreadsheets offer practical and efficient computational solutions for the Henssge equation.
• These tools enhance the accessibility and accuracy of postmortem interval estimation in forensic science.
• The availability of these digital tools supports forensic practitioners in their investigations.